In known connection systems which use clamps fixed by nuts, it is difficult to change one of the elements since the pipework for compressed air which is made of metal and which is connected to the first and to the second elements do not readily let one clamp move away from the other. The metal pipework thus needs to be unscrewed in order to change an element.
Further, it is not possible to point one of the elements in any desired direction relative to the other in order to move a control member connected to the element being moved into a better position to be operated by an operator.
Preferred embodiments of the present invention make it possible to avoid these drawbacks.